1. Field of the Invention
The present invention relates to a VME Slave Tester, and more particularly, to a VME Slave Tester interfacing to a standard VMEbus to assist a user in determining the source or cause of a problem related to specific hardware connected to the VMEbus and its associated software. The present invention performs this operation by monitoring data transfers to and from selected addresses of a VME slave module.
2. Background of the Related Art
A few years ago there did not exist any analyzers which were designed specifically for the VMEbus protocol. Instead, a variety of general-purpose logic analyzers were available for determining the cause of a problem in a functional module connected to an interface bus.
These general-purpose logic analyzers contain a wide variety of features and consequently, possess major disadvantages in size, cost and operational complexity. Specifically, the typical size and weight of general-purpose logic analyzers makes them inconvenient to transport and store. In addition, general-purpose logic analyzers are prohibitively expensive if only used for trouble-shooting functional modules connected to a VMEbus, since these analyzers contain many additional features which are not needed. Further, to utilize an analyzer effectively, the analyzer must be configured for a given set of tests. This configuration involves establishing various parameters to indicate the specific signals to analyze, the timing period of the sampling clock, and the conditions for triggering the analyzers. This complexity of configuring general-purpose analyzers for analyzing data relating to the VMEbus seriously limits their use in diagnosing whether a VME slave module has defective hardware or software.
The VME Slave Tester, which is the present invention, is more suitable than a general-purpose logic analyzer in trouble-shooting errors in functional modules connected to the VMEbus. Specifically, a general-purpose analyzer is able to determine the source of an error in a VME card already known to be defective. However, the VME Slave Tester is better suited for initially localizing the source of an operational problem in a complete functional VME system. Using the VME Slave Tester, the source of a problem can be more easily tracked to a specific functional module and it can be determined whether the error is caused by the module's hardware or its associated software. Once the error is identified as a hardware or software problem, the problem can be quickly corrected. For instance, if the hardware is defective, a new VME slave board can be inserted into the VME system to replace the defective VME board. In addition, if the VME Slave Tester determines that the problem is in software, the software can then be debugged to permit the VME system to return to full operation. Thus, the VME Slave Tester permits a VME system having hardware or software failures to be brought back to full operation efficiently and quickly. Hence, the VME Slave Tester of the present invention is superior to the general-purpose analyzer in initial VME problem identification. Further, general-purpose analyzers are not designed to replace the module which is being analyzed, as is the present invention.